Inspection of electrodes and separator membranes

The goals laid out by the German government are ambitious: One million electric vehicles on German roads by 2020. However, before the electric vehicles can conquer the roads, their electric motors, components, and batteries will have to undergo stringent testing. Today, powerful automatic inspection systems play an important role in shortening the way to e-mobility and ensuring its implementation.

The best possible energy yield and reliability is the goal to be reached when developing lithium ion technology batteries. In consequence, highest quality requirements for each and every battery component, from the anode, the cathode, to the separator film need to be fulfilled. The solution is a 100% optical inspection of production for a wide variety of defects, including holes, streaks, thin applications, irregularities, coating defects and more. The expense is justified, only 100% defect-free lithium ion batteries are capable of achieving their full performance, capacity and expected life. Moreover, any defect would present a serious safety risk. Holes in the separator film, for example, can cause a fire and a total battery failure.

Longstanding expertise in separator foils

ISRA VISION has been supplying systems for quality assurance in the field of general battery production for more than 20 years. The industry expertise and processing skills gathered during that time can now be used to the benefit of developments made in the field of electric mobility. The key to success lies in the ability to supply safe and powerful energy storage media. Separator film plays a major role in this context. In fact it represents one of the most important components of any battery. Even the tiniest of holes in the 0.05 mm diameter range must be detected during production and in the subsequent cutting steps, even at web speeds of several hundred meters a minute.

While at the dawn of the development the ability to detect holes was the primary goal, the focus has now shifted to finding and classifying additional defect types. Not only does the technology have to recognize holes, but now it also has to discover defects such as thin applications, impurities, scratches, uncoated areas of the material, streak defects, folds, and more. The systems offered by ISRA are designed to reliably differentiate between the various defect types. To meet market demands, the company developed a special optical concept and a high-level classifier (Quickteach). These tools make it possible to obtain a wide range of information very early. As soon as an image of a material defect is captured it will be automatically classified. The concept functions independent of the web speed and can even be used, for example, on fast running cutting / finishing equipment.

Additional tools support production improvements

The method can be combined with a variety of software tools to improve production such a cutting optimization module or a rewind manager. The latter allows the user to define certain defects that need to be removed from the inspected reel material. Another special software package (Quality Review) guarantees that flawless daughter rolls are delivered. The tool can even be used by the manufacturer as an aid when dealing with customer returns. The delivered quality can be demonstrated with absolute certainty at any time.

High efficiency and productivity with inspection solutions

The ISRA inspection solutions and their integrated tools guarantee that any defects that occur during the production of battery components, separator film or electrodes for example, are correctly and reliably identified and classified. As such, the conditions are in place to guarantee the best possible quality as well as production efficiency. In view of the increasing number of suppliers in this lucrative market, this step is critical in assuring that manufacturers stay ahead of the competition.

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